Messages in this thread |  | | Date | Thu, 2 Apr 2020 16:17:31 -0700 (PDT) | From | Daniel Jordan <> | Subject | Re: [PATCH] mm: thp: don't need drain lru cache when splitting and mlocking THP |
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On Thu, Apr 02, 2020 at 07:04:11PM -0400, Daniel Jordan wrote: > On Sat, Mar 28, 2020 at 03:29:40AM +0800, Yang Shi wrote: > > Since the commit 8f182270dfec ("mm/swap.c: flush lru pvecs on compound > > page arrival") THP would not stay in pagevec anymore. So the > > optimization made by commit d965432234db ("thp: increase > > split_huge_page() success rate") doesn't make sense anymore, which tries > > to unpin munlocked THPs from pagevec by draining pagevec. > > > > And draining lru cache before isolating THP in mlock path is unnecessary > > either. > > Can we get some of that nice history in this part too? > > Draining lru cache before isolating THP in mlock path is also unnecessary. > b676b293fb48 ("mm, thp: fix mapped pages avoiding unevictable list on mlock") > added it and 9a73f61bdb8a ("thp, mlock: do not mlock PTE-mapped file huge > pages") accidentally carried it over after the above optimization went in. > > > Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > > Cc: Hugh Dickins <hughd@google.com> > > Cc: Andrea Arcangeli <aarcange@redhat.com> > > Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> > > Since we don't mlock pte-mapped THP, it seems these huge pages wouldn't ever be > in the pagevecs if I'm understanding it all.
Actually pte-mapped THP doesn't matter for this, both paths always drain when they're working with pmd-mapped THP.
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